Hover shows only partial python bpy. path
In such cases you could have a look at the source code. Click RMB while the mouse cursor is over the property to open the context menu, select Edit Source.


Open a text editor and select the loaded file, you will notice that the cursor is already positioned at the property.
In this case the line is:

sub.prop(cbk, "use_selected_to_active") (line:1258)


Ok, this is what you already knewd , the cbk is another variable holding the context of this property a few lines above (line:1242) you will find the definition.

cbk = scene.render.bake


Now you can assemble the parts to the full path and test it in the console window:

&gt;&gt;&gt; import bpy
&gt;&gt;&gt; print(bpy.data.scenes["Scene"].render.bake.use_selected_to_active)
True


Note: Line numbers are valid for official 2.71, One could have used the D shortcut for bpy.data.